This document discusses the principle of rhythm in design. It defines rhythm as continuous, recurrent, or organized movement that allows for underlying unity and variety in a design. The document explains that rhythm can be created in five ways: by repetition, gradation, transition, opposition, and radiation. Each type of rhythm is then described in more detail with examples. The key point is that rhythm creates movement in the eyes as they flow across an object or space in an organized way. Readers are assigned a project to find examples that illustrate each type of rhythm.